This invention relates to a gear shaping machine of the type in which a toothed shaping cutter on a rotatable cutter spindle is reciprocated back and forth relative to a workpiece on a rotatable work spindle in order to form gear teeth or the like on the workpiece. The two spindles are rotated in timed relation with one another to cause the gear teeth to be spaced around the periphery of the workpiece and to equalize the wear of the teeth of the shaping cutter. As the cutter is reciprocated, it is moved laterally toward and away from the workpiece in order to cause the cutter to engage the workpiece during an active cutting stroke and to clear the workpiece with relief during an inactive return stroke. Also, a relative infeeding motion is imparted to the cutter and the workpiece in order to increase the depth of cut of the cutter into the workpiece as the gear teeth are generated.
Most present-day commercial gear shaping machines are adapted to be used with several different types and sizes of shaping cutters and are adapted to be changed over to enable the formation of a wide range of different types and sizes of gears. While such a machine is extremely versatile, that very versatility causes the overall construction of the machine to be both complex and expensive. For example, an elaborate gear train with several sets of change gears is required for driving the cutter and work spindles in the various timed relationships necessary to form different types of gears. Also, various other adjustment features add to the cost and complexity of the machines. Such cost and complexity are of little value to a gear manufacturer who wishes to make only a single type of gear or a very narrow range of gears.